2003 G35 code U1000 and U1001.

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QCtech
Posts: 102
Joined: Wed Mar 22, 2017 9:43 pm
Car: 2003 Pathfinder LE

2003 G35 code U1000 and U1001.

Postby QCtech » Sun Jun 11, 2017 8:25 pm

I just bought a 2003 G35. It have the codes above. These codes are no can communication. Both the slip and the AT light are on all the time as soon as I turn it on. It is also on limp mode or so it seems because it is on 2nd gear and wont go above that, also the gear selector screen is in blank in both auto and manual mode. I checked under the battery and found some interesting things. First , the IPDM starter relay have been bypassed and a direct cable put on it to the starter. It seems they also did some repairs on some of the battery white cables and spliced a few. There is also a green/red cable from the main harness that seems a little frayed and I identified as part of the can bus communication.There is another black cable that is broken , but I can not find the other end or where it came from. It is a total mess. They did not shield any of this cables after the sorry intent of repair and the water drain under the battery was clogged. I suspected at the beginning that the TCM was bad due to the AT light on all the time, but now I think this is something else. According to the guy that sold it to me, they only (repaired a battery cable) before. Now he could not give me a lot of info because this car was from his son. He said that this "repair" was done around october, and he forgot that he already had txt me that the car was garaged since october when I first contacted him, so my theory is as follows. I guess that this car had starting problems at first, and was taken to a half a cent mechanic that found that the starter relay was bad, and instead of properly replacing it, decided to do the dirty started bypass. He did not even fit it properly,the cable was basically hanging from one of the legs of the relay.I think this either shorted the ipdm or that the car ipdm or ecu registered the bad relay and entered limp mode. I guess some of the cables of the can bus are fried or maybe the ipdm is not communicating. I will know when I do some more troubleshooting. I am going to get this relay new first and then see if it starts with it, and if it does not then open the ipdm and see if there is water damage. Infiniti did a terrible job of putting that IPDM in that area with the small drain that clogs easily. I have read a lot about water damage in that area and dead IDPM. The car also have 165k. I hope it is only repairable wiring and not a real transmission problem. Other than that , they told me they had repaired the air conditioning and I noted it does not have the original radio console and it seems that they used an aftermarket console to eliminate the radio console. The car starts and the engine sounds great with the jumper, but that is damaging everything else I think. If anyone have some pointers or help regarding this or have been thru this road , please chime in and give me some advice. Thanks.


ca18det_boy
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Location: Homestead, FL

Re: 2003 G35 code U1000 and U1001.

Postby ca18det_boy » Mon Jun 12, 2017 1:49 pm

I'm sorry you're having to deal with this. I absolutely hate fixing wiring that other people "repair". Might be worth it to go to town with a multi meter and make sure that none of the wiring burnt up.

QCtech
Posts: 102
Joined: Wed Mar 22, 2017 9:43 pm
Car: 2003 Pathfinder LE

Re: 2003 G35 code U1000 and U1001.

Postby QCtech » Mon Jun 12, 2017 7:12 pm

Im already doing that. Going by the manual I already measured continuity to the IPDM. I am guessing it is my TCM, but I wont get another TCM until I finish all the measurements and find that all the wiring to it is ok.The starter relay on on the IPDM is actuating, so I dont think that is the problem.The only weird thing about that relay is that the coil resistance is higher than what the specs of the relay says, but I measured the adjacent relays which are similar and all of them,the coils reads higher. For what I am reading in the schematic, it seems that the TCM sends the signal for the starter relay in the IPDM. Not 100 percent sure about it but looks like. If anyone have done this before and can help some let me know.

QCtech
Posts: 102
Joined: Wed Mar 22, 2017 9:43 pm
Car: 2003 Pathfinder LE

Re: 2003 G35 code U1000 and U1001.

Postby QCtech » Thu Jun 22, 2017 12:48 am

Update--- Fixed this problem. They did a lot of dirty cable work in this car previously. My NCIS skills found out that they have changed the headlamps for aftermarket ones and did a poor wiring job, and one ground cable fried itself all the way back thru the main harness. The way they repaired this cable was worst than the original problem, a lot of s*** splices and a lot of tape. This somehow made the TCM fuse to burn and the car was not starting. Then it seems the previoud owner took it to a 2 cent mechanic to repair it and since he was too lazy to see the TCM fuse was blown , he just put a jumper cable from the starter to the starting relay. Then the car was starting but in limp mode and wont go past 2nd gear. After fixing all the wiring, and changing the fuse, it is all good now. I cleaned , repaired and properly routed all the cables in the main harness and also cleaned my IAV because it was so dirty that the car was stalling when first started. After the proper cleaning and idle relearn it is all good now.The code U1000 and 1001 was simply the ECU not receiving can bus info from the TCM because the fuse burned. The car is in very nice condition for the milleage , it just seem that it had previous owners that only knew to put gas on it and nothing else. I got a nice running G35 now for a very low price because of a cheap mechanic not knowing what he was doing. Life is good.

5050king
Posts: 2
Joined: Fri May 25, 2018 6:25 pm
Car: 2006 m35x

Re: 2003 G35 code U1000 and U1001.

Postby 5050king » Tue Feb 26, 2019 10:41 am

Where is the tcm fuse located

04pathse
Posts: 753
Joined: Sun May 02, 2010 2:55 pm
Car: 2004 Nissan Pathfinder SE
2008.5 Mazda Mazdaspeed 3

Re: 2003 G35 code U1000 and U1001.

Postby 04pathse » Wed Feb 27, 2019 12:09 am

5050king wrote:
Tue Feb 26, 2019 10:41 am
Where is the tcm fuse located
]

should be in the engine compartment

5050king
Posts: 2
Joined: Fri May 25, 2018 6:25 pm
Car: 2006 m35x

Re: 2003 G35 code U1000 and U1001.

Postby 5050king » Mon Mar 04, 2019 6:27 am

04pathse wrote:
Wed Feb 27, 2019 12:09 am
5050king wrote:
Tue Feb 26, 2019 10:41 am
Where is the tcm fuse located
]

should be in the engine compartment
i have an m35 2006 with same problem all fuse work i had to towed to dealership last week and im waiting for a call back


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